rfc:numeric_literal_separator

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rfc:numeric_literal_separator [2019/05/27 16:37] – Tweak examples theodorejbrfc:numeric_literal_separator [2019/06/14 09:42] – Implemented nikic
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   * Author: Theodore Brown <theodorejb@outlook.com>, Bishop Bettini <bishop@php.net>   * Author: Theodore Brown <theodorejb@outlook.com>, Bishop Bettini <bishop@php.net>
   * Based on [[https://wiki.php.net/rfc/number_format_separator|previous RFC]] by: Thomas Punt <tpunt@php.net>   * Based on [[https://wiki.php.net/rfc/number_format_separator|previous RFC]] by: Thomas Punt <tpunt@php.net>
-  * Status: Under Discussion+  * Status: Implemented (in PHP 7.4) 
 +  * Discussion: https://externals.io/message/105714
   * Target version: PHP 7.4   * Target version: PHP 7.4
   * Implementation: https://github.com/php/php-src/pull/4165   * Implementation: https://github.com/php/php-src/pull/4165
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 ===== Unaffected PHP Functionality ===== ===== Unaffected PHP Functionality =====
  
-Underscores in numeric literals will be stripped out during the +Adding an underscore between digits in a numeric literal will not 
-lexing stage, so the runtime will not be affected.+change its value. The underscores are stripped out during the lexing 
 +stage, so the runtime is not affected.
  
 <code php> <code php>
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 literal, which allows searching for a value like "_6F_" to find only literal, which allows searching for a value like "_6F_" to find only
 the numbers containing that specific byte. the numbers containing that specific byte.
 +
 +==== Should it be the role of an IDE to group digits? ====
 +
 +It has been suggested that numeric literal separators aren't needed
 +for better readability, since IDEs could be updated to automatically
 +display large numbers in groups of three digits.
 +
 +However, it isn't always desirable to group numbers the same way.
 +For example, a programmer may write ''10050000'' differently
 +depending on whether or not it represents a financial quantity stored
 +as cents:
 +
 +<code php>
 +$total = 100_500_00; // represents $100,500.00 stored as cents
 +
 +$total = 10_050_000; // represents $10,050,000
 +</code>
 +
 +Binary and hex literals may also be grouped by a varying number of
 +digits to reflect how they are used (e.g. bits may be separated into
 +nibbles, bytes, or words). An IDE cannot do this automatically
 +without knowing the programmer's intent for each numeric literal.
  
 ==== Why resurrect this proposal? ==== ==== Why resurrect this proposal? ====
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 Andrea Faulds summarized the considerations [[https://externals.io/email/90673/source|as follows]]: Andrea Faulds summarized the considerations [[https://externals.io/email/90673/source|as follows]]:
  
-> This feature offers some benefit in some cases. It doesn't introduce +<blockquote> 
-> much new complexity. There's no new syntax or tokens, it just modifies +This feature offers some benefit in some cases. It doesn't introduce 
-> the form of the existing number tokens. It fits in well [with] what's +much new complexity. There's no new syntax or tokens, it just modifies 
-> already there, consistently applying to all number literals. It follows +the form of the existing number tokens. It fits in well [with] what's 
-> established convention in other languages. Its appearance at least hints +already there, consistently applying to all number literals. It follows 
-> that values with these separators are not constants or identifiers, but +established convention in other languages. Its appearance at least hints 
-> numbers, reducing potential for confusion. It limits its own application +that values with these separators are not constants or identifiers, but 
-> to prevent abuse (no leading, trailing, or repeated separators). And +numbers, reducing potential for confusion. It limits its own application 
-> it's relatively intuitive.+to prevent abuse (no leading, trailing, or repeated separators). And 
 +it's relatively intuitive. 
 +</blockquote>
  
 ==== Comparison to other languages ==== ==== Comparison to other languages ====
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 ===== Vote ===== ===== Vote =====
  
-Add numeric literal separators in PHP 7.4? Yes/No.+Voting started 2019-05-30 and ended 2019-06-13. 
 + 
 +<doodle title="Support numeric literal separator in PHP 7.4?" auth="theodorejb" voteType="single" closed="true"> 
 +   * Yes 
 +   * No 
 +</doodle>
  
 ===== References ===== ===== References =====
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 Discussion from previous RFC: https://externals.io/message/89925, https://externals.io/message/90626, https://marc.info/?l=php-internals&m=145320709922246&w=2. Discussion from previous RFC: https://externals.io/message/89925, https://externals.io/message/90626, https://marc.info/?l=php-internals&m=145320709922246&w=2.
  
-Blog post about implementation: https://phpinternals.net/articles/implementing_a_digit_separator.+Blog post about original implementation: https://phpinternals.net/articles/implementing_a_digit_separator.
rfc/numeric_literal_separator.txt · Last modified: 2019/08/19 19:58 by theodorejb

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